Gearing.



K. ALQUlST.

GEARING.

APPLHIATION men JAN. 11. 1914.

Patented Dec/28,1915.

KARL ALQUIST,

0F SCHENECTADY, NEW YORK.

GEARING.

Application filed January 1 To all whom it may concern.

Be it known that I, KARL AL UIsT, a subject of the King of Sweden, residing at Schenectady, county of of New York, have invented certain new and useful Improvements in Gearing, of which the following is a specification.

My invention relates to gearing such as is used for the transmission of power and 'for speed reduction or magnification for an almost unlimited variety of purposes, in cluding the driving of dynamo electric machines and of marine propellers by steam turbines, etc.

he invention is concerned both with individual gears of very general utility and with trains of gearing whose functional advantages are increased and enhanced when they include individual gears such as my invention contemplates. Among the advantages obtainable through my invention are equality of loading and wear among gears arranged in parallel; minimization of the ill effects arising from inaccurate location of bearings and other similar errors; uniformity of loading and wear among the teeth of individual gears; smooth, ning; and others that come apparent.

In the case of two or more gears arranged in parallel so as to be driven by or to drive a common gear, it is impossible to secure substantially and uniformly equal division of load among the gears and so avoid danger of overstraining their teeth, etc., unless the teeth of both the parallel gears are in contact with those of such common driving or driven gear with substantially the same average tooth pressure; and for the best results it is necessary that the tooth pressures should be actually equal at all points as well as of the same average value. In ordinary gearing, equality of the average even, noiseless runw ll hereinafter beand maintained in positions, while actual and uniform equality of the tooth pressures depends, in addition, on uniformity and exact similarity of their teeth as regards both form and spacing.

Specification of Letters Patent.

Schenectady, State Patented Dec. 28, I915.

7, 1914. Serial No. 812,812.

In accordance with my invention,

I provide for relative a d ustment of parallel gears to secure equality of average tooth any of the gears and affording various other advantages. make at least the toothed portions nae or disks arranged side b with a common driving or the like, portions though, generally speaking, they turn with their hub or shaft in a substantially fixed angular relation so as to transmit power to or from it effectually, yet they may upon occasion yield of one in lamiy side in mesh driven-gear or mounting or securing the toothed f advantage that the toothed members should be caused turn with their hub connecting means, since such means will upon occasion be capable of advancing a member about the hub or shaft spiral or preferable for h g tage to provide this last feature, howto gears whose toothed parallel with them, for

In such special gears, I may or members in such wise that alor shaft by resilient yieldingly secured to turn In the accompanying drawing, Figure 1 shows a multiple reduction train of gearing constructed in accordance with my invenfra mentary axial section construction of aspecial gear such as may be used in the train shown in Fig. 1 Fig. 3 is a view of one of the gear members shown in section in Fig.

eneral view of a gear more or less like that shown in Figs. 2 and 3. Fig. 5 is a fragmentary detail view of the periphery of a gear member, on a further enlarged scale, the teeth being in section at the pitch line.

The train of gearing shown in Fig. 1 comrises a small driving gear 1, a large gear 2 to be driven at a reduce speed, and driving connectionsbetween them consisting of a pair of coaxially arranged gears 3, 4 cured on their shaft 5 in substantially fixed angular relation to one another and a pair of identically similar gears 6, 7 similarly mounted on their shaft 8 The gears 3 and 6 are about five times as large as the gear 1 and the gear 2 is about three times as large as the gears 4 and 7, so that the speed reduction between the gears 1 and 2 is about 15 to 1. As shown, the teeth of the gears 1 and 3 and 4 and 2 have the proper'bearing for the directions of rotation indicated; but although the teeth of the gears 1 and 6 bear properly for driving by the'former, those of the gears 7 and 2, which are shown out of mesh for the sake of clearness, are not in such relative positions as to bear properly for driving of the latter by the former when brought into mesh position by shifting of the shaft 8 toward the gear 2 If the angular distances between the teeth of the gears 6 and 7 that are nearest to angular coincidence were everywhere the or 3 and 4 on same, this condition and the consequent failure of the gears 6 and 7 to carry their part of the load could be remedied only by shifting of bearings or readjustment of the angular relation of the gears 6 an their respective shafts. As shown, however, the angular distances of the teeth of the gears 6 and 7 (and also of the gears 3 and 4) that are nearest to angular coincidence is different in different parts of their peripheries, so that the shaft 8 from its bearing, turning it a little, and replacing it,-repeating this operation as often as necessary,--substantially proper bearing between the teeth of the 7 and 2 can be secured without impairment of that between the teeth of the gears 1 and 6 or disturbance of the gears 1, 3, 4 and 2. Ilhe greatest degree of refinement in this adjustment can be secured by making the number of teeth in the gear 3 just one more or one less than an exact multiple of the number in the gear 4, as shown (or conversely), and by making the 2. Fig. 4 1s a.

ranged side by side united with the inner part or ring by taking tooth pitch as small as other considerations render expedient. If the adjustment fails to produce an exact equality of loading between the parallel driving connections, it

-will at least minimize the inequal1ty,-be-

possible to have all the sides making it simultaneously,

various gears intermesh even in extreme cases.

Nothing has so far been said about the character or the construction of the various gears shown in Fig. 1, since the advantages above set forth can be realized with any accurately cut gears. For reasons already more or less fully indicated, however, prefer that at least one of the gears 3 an 6 should be of a special construction such as is illustrated in Figs. 2 and 3. In the particular construction shown, such special gear comprises a number of sections arin mesh with the gear 1 and themselves comprising separate ring members 10 secured to turn with the shaft 8 through resiliently yielding metallic connections to ring-like hubs 11 keyed on a sleeve 12 that is itself keyed fast on the shaft 8. While various modes of construction and various forms of spring connection can be used, I prefer forming the parts 10 and 11 of each gear section from a common disk of metal and using part of this disk itself to form the spring. This may be done by milling out slots 13 between the inner and outer portions of the disk in such a way that these parts are finally connected only by an intermediate spring ring 14 o nearly a complete turn, at the one end united with the gear ring 10 and at the other end 11 (Fig. 3), which is, in turn, fixed to the shaft 8 as already described.

The gear ring or member must in any case be centered or supported about the shaft 8, which can be done by another ring 15 fitted between it and the hub 11. As shown, the spring portion 14 is turned down to about one-half of the thickness of the outer and inner rings 10 and 11 and the centering ring 15 is-fitted in the recess or space thus formed, so as to be held from the central part 11 and serve as a bearing for the gear ring The gear sections (the hubs 11 being free to move lengthwise on the sleeve 12, although constrained to turn with it) are held between stiff end supports 16 and 17 (Fig. 3), which with the sleeve 12 are held in place by nuts 18 (only one being shown) threaded on the shaft 8. The sleeve 12 may be made of such length that some slight play will be afforded the gear sections; or the whole system may be comressed axially to some extent so as to damp oscillations. To revent wear, the gear be flooded with oil from the As shown, there are a number of diagonal passages 19 runningfrom an annular trough or oil catcher 20 1,165,827 are of straight spur gearing. That is to say, the on the end support 16 into the lnner porload tions of the slot 13, so that the oil will be fe in y centrifugal force and circulate out between the parts to the periphery of face passes through a plane passing through the gear. t e centers of the two gears. At all other While a gear constructed as above set forth may be of either straight or helical toothed type, special advantages can be obtained by embodying in it the principles of the type of axially flexible helical gearing described in British Patents 28,801 of 1910 and 17,244 of 1911. With a gear thus constructed, the axial deflection of the teeth or the toothed portions of the gear laminae or disks and the resultant slight circumferential deflection serve principally to give a times the pressure is transmitted above or below the pitch line where there is'a sliding action between the two teeth. In order to obtain the special advantages of the helical type of gearing with the laminated or disk construction while retaining the advantage of flexibility and avoiding certain difficulties present in connection with the running of such gearing, it is important, I have found, so that the teeth of each disk should have a certain axial widtl depending upon the tooth pitch and the angle of the teeth with pitch-line contact, and preferably but a sinyielding of the gear laminae or disks serves gle continuous pitch-line contact. This of sudden load widthis determined by what may be called changes, poor shaft alinement, and other t e principle of continuous pitch line: 2'. 6., errors due to faulty workmanship, etc., each disk should have such a width that the although neither the axial flexibility nor the projection on a plane at right angles to the direct rotary adjustment of the gear disks axis of the gear of all the pitch lines of the performs exclusively the unctions mentioned. As shown, axial or lateral flexibility is obtained by reducing the thickness of the ring members 1010a either side, so that surfaces of the contact sides of the teeth local bending may take place at the thin part 21. While the inner portions of the along a line parallel with the axis, the drive line, as the gears revolve. This principle tions, so that there Will be a space between may also be stated in another form b saythem. The stiff end supports 16 and 17, it ing that each individual disk should carry will be seen, are of smaller diameter than the load at any time only on one single (theoretical) pressure point, being a point common to the drlvmghne and the pitch t 1s usually preferable that helical gears line,-or that, in other words, the number Should be of the double or divided herringof pitch line pressure points in the whole bone type, in order that they may be balgear should be equal to the number of disks. anced asi'egai'ds axial thrust, and the gears he required axial width will be given by 4 and 6 are supposed to be gearsof this sort. the equation: Such a divided gear is somewhat diagramthem of less thickness than the inner porbzp/tan a where b=axial tooth width for a section, p=circumferential tooth pitch and-a= angle of teeth with axis.

In practice it is advisable to add about oming, now, to the matter of the axial width of the teeth of this or any other form of laminated laterally flexible helical gear, I have found that when a 10% to the theoretical width given for reagear is built up from a group or pack of sons of strength of the teeth against excescomparatively thin laminations or disks the sive bending. so that the full load may individual teeth in a given lamination run; never be carried just at the end of a tooth in certain respects under conditions approxwhere it is weakest. This will. of course. imating those of ordinary straight teeth and add to the length of the gear, but on acunder similar disadvantages, although the count of-the relative increase in strength of teeth are cut helically across the pack of the teeth thus obtained a smaller pitch may laminations. In particular, the essential be used. which more than makes up for the characteristic of the helical type as usually additional length by increasing the wearing constructed, is practically missing, and the surface. as now there will be more teeth work is distributed over the whole tooth crossing the driving line per unit length. surface in much the same way as in the case The combination described gives about the maximum power transmission obtainable tooth flexibility would help in the equalizafor a certain size of gear. tion of the load. Of the gears 3, 6 and 4, 7,

The fore oing equation and remarks are .it is preferable that one of the former illustrated y Fig. 5, which gives a someyielding.

5 what diagrammatic view of a portion of the In accordance with the provisions of the '70 rim of a gear section, the teeth being shown patent statutes, 1 have herein set forth the in section at the pitch line. Here the line principles of my invention and described G-D represents the driving line, and p the best embodiment thereof at present and a are respectively the circumferential known tome. While, however, the inveno tooth pitch and the helical angle of the tion extends to the particular apparatus teeth. The theoretical width is b, the width described and its various specific features added for practical reasons as above set and details and novel combinations and arforth is e, and the total actual, practical rangements of parts, it is not confined width is thus I) plus 6:17,. The load is thereto, but can be'otherwise carried out s simultaneously carried at 6 and 6 and embodied. 80

A pressure, point, as previously described, What I claim as new and desire to secure is the intersection between the line G-D by Letters Patent of the United States, isand a pitch line, and it will be understood 1. A gear comprising a plurality of laterfrom the figures that when the disks really flexible helical toothed members arvolve (the driving line being stationa y) ranged side by side with the toothed portions 85 such a pressure point will move along a free to yield, the teeth of each member being plitch line as this line crosses the line CD. substantially of such a width as to give conach disk will, therefore, have only one tinuous pitch line contact and said members ressure point on the main or middle portion being secured to turn with their shaft so as of its face or width for transmitting the load to be capable of yielding independently of 90 at any time, but will have two pressure one another by way of rotary adjustment oints on parts 6, and e while the load is relative to said shaft. shifted .from one tooth to the next. Fi 2. A gear comprising a helical toothed 2 shows the teeth in such osition with re member whose toothedportion is laterally erence to the driving line D that, the two flexible and free to yield and a metallic 95 pressure point period is just commencing, spring connection between said member and one pressure pointbeing at f and the other the gear shaft whereby the former is caused about to start at g. to turn with the latter.

It will be understood that if the width 3. A gear comprising aplurality of helical 5 of the sections is increased substantially flexible toothed members arranged side by 100 beyond the dimensions given, the load for Side and secured to turn with their shaft o a given gear disk will be carried the one as to be capable of yielding by way of rota moment on two points and th xt o t ad ustment with reference thereto indepen on one point, thus giving unequal surface en y of on another. load. If the width were increased so that 4. A g ar comprismgaplurahty of toothed in: two points were theoretically always carrymembers arranged s de by side and seing the load; i. 6., if the width were doubled, cured to turn with their shaft through lESll-' this would at first sight seem to be an ently yielding metallic connections, so that cepta'ble condition, but, apart from other they shall be capable of'independent rotary disadvantages, it will be found that as a adJustment relative to said shaft when the 110 rule only one point carries the load of the ooth pressure Varies.

' section, owing to the deflection, and a 5. A gear comprising aplurality of toothed larger pitch would have to be chosen for members arranged side by side and each reasons of strength, involving loss in wearsecured to turn with their shaft by meanso ing surface, and in general practice such a a spring extending from a connection with 11; ear will be considerably inferior to the one said member atone end around the shaft to ressure point type described. I do not a COIIDGCtIOII with the same, said members claim herein the invention as related to the being centered on the shaft independently of I width of disks as just described since this heir onn c lng Springs.

forms the subjectmatter of my divisional 6. A gear compr sing a plurahtyof gear 12 application Serial No. 25,513, filed May 3, sect ons arranged side by side and each com- 1915. Neither do I claim herein the invenprising a hub secured to the shaft, a toothed tion as related to the train of gearing 'as ring, and a spring ring connecting them, this is embodied in my continuing applicasa dparts being in one p ece and the spring tion Serial No. 36,961, filed June 29, 1915. being formed by the cutting of slots there n. 1

Referring once more to the train of gears 7. A gear comprising a plurality of gear shown in Fig. 1, it is preferable that when disks arranged side by side and each coma yielding gear is used it should b on of prising a toothed ring portion, ahub portion,

the parallel gears rather than either of the and an intermediate spring ring portion of gears 1 and 2, since in the former case only less thickness than said ring and said hub 31 ti 0ns being laterally flexible and free to 10 yield.

In Witness whereof, I have hereunto set my hand this 16th day of January, 1914.

KARL ALQUIST. lVitnesses: HELEN ORFORD,

MARGARET E. WOOLLEY. 

